Flexible packages of the type ‘flow pack’ are well known. In their simplest form they are formed by wrapping a continuous web of material about its longitudinal axis and then joining the longitudinal edges of the web so that they form a joint extending along the longitudinal axis of the web. The wrapping is made around the intended contents. The thus formed tube is partitioned off to form a closed pocket by means of upper and lower transverse joints. A package of this type can also be made by wrapping the material into a tube which is partitioned off to form a pocket by means of a first transverse joint forming the bottom thereof. The pocket is filled with its contents and closed by means of a second transverse joint forming the top thereof.
One way of opening this type of package is by tearing off a corner or tearing apart one of the trans-verse joints. Such opening is difficult to control, since the material in the worse case scenario is torn in an uncontrolled manner, fully destroying the package. Also, it does not allow for resealing.
Resealable packages of this type using a flap and seal are known. A typical flap, indication and label are disclosed in U.S. Pat. No. 4,874,096. The package is a ‘flow-pack’ having an arcuate indication which defines the flap. The flap is covered by a resealable label. Further examples of documents describing this type of packages are WO86/06350 and EP 0 193 130.
The typical solution in these prior art resealable packages is to provide a flap in the package wall whose delimitation corresponds to the desired opening. The delimitation consists of an indication, which may be an area of locally thinner material, a perforation or a through slit. A self-adhesive label covers the flap and the indication. The indication, combined with the self-adhesive label, gives the package a controlled opening geometry and an opening that can be easily resealed. This solution however requires the indication to be smaller than the width or length of the package, depending on the orientation of the flap, since the label must cover, not only the indication, but also an area surrounding said indication. This involves problems to be explained below.
In the filled condition the walls of the package will conform to, and more or less follow the geometry of the object. Accordingly, also the indication and the label will conform to the geometry, making the width of the package and the opening seen in a horizontal plane more narrow. Supposing the object is a rectangular parallelepiped, there is a risk when pulling out the object through the opening, that the object will get stuck inside the package since the opening is too small. Even if it is possible to pull out the object, there is a risk that the corners of the object will tear the material and destroy the package. There is also a risk of damaging the object. The latter is especially the case if the object is easily damaged or rigid, e.g. slices of cheese or a printed circuit card.
One way to solve this is to increase the size of the package compensating for the conforming to the contour of the object. However, a larger package means superfluous use of material and a flapping, generally less aesthetic look.
It is admittedly possible for the indication to cover the full, or almost full width or length of the package. However, in that case the label must be applied and folded over from one wall to the other. This is especially the case if the label should cover the full extent of the indication, including any tearing lines that are formed during opening. Such label is hard to apply in high-speed production. There is a risk that the conformation of the side walls to the geometry of the object creates tensions damaging the indication, and it is hard to reseal the package. Further, if the indication is arranged in the longitudinal direction, there is no natural stopping means when tearing the material, unless the longitudinal joint, which generally is applied on the back wall, is repositioned in accordance with the desired shape and orientation of the flap.
Based on the above discussed problems, packages of the ‘flow pack’ type are generally not used for easily damaged or rigid objects where access to the full width or length is required through the opening. Instead different types of flexible or rigid deep drawn packages are used having a lid-like closure. This type of packages allow an opening to be formed across the full width/length or area of the mouth of the deep drawn package. This is however a type of package being different from the ‘flow pack’ type.